JPH0465321B2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The article positioning method of the present invention is applicable when measuring the shape of an article such as roundness, when performing high-precision processing on an article, or when measuring a high-precision article. Can be used when assembling.

(Background Art) In order to measure, process, and assemble the shape of an article, for example, the center position of the article may be determined. Conventionally, the center position of the article has been determined as follows.

First, when an article is cylindrical and the center position is determined based on the inner circumferential surface of the article, methods such as those shown in FIGS. 1 to 3 are often used. In the example shown in Fig. 1, a cylindrical article 1 whose center position is to be determined is fitted onto a cylindrical positioning pin 2, and in the example shown in Fig. 2, the center position is placed on a truncated conical pin 2. This is an object in which the object 1 whose position is to be determined is fitted onto the outside. In each example, the center of the pin 2 is determined as the center of the article 1 fitted onto it. However, when determining the center of the article in this way, in the example shown in FIG. 〓The measurement result will deviate by the amount in between. Further, in the example shown in FIG. 2, the support of the truncated cone-shaped article becomes unstable, which inevitably causes errors in the measurement results. Furthermore, as shown in the example shown in FIG. 3, there is a method in which the inner peripheral surface of the cylindrical article 1 is held down by pneumatically or hydraulically driven chuck claws 3, 3, and the center of the chuck is determined as the center of the article. So, even when using the most accurate chuck currently in use under the best conditions, the measurement accuracy is about 1 to 3 μm.
In reality, large errors occur in the measurement results due to errors in the shape of the article and variations in the force applied to the claws 3, 3. Furthermore, since the claws 3 are pressed against the article 1 over a narrow area, the inner surface of the article is likely to be damaged.

Further, when the article is columnar and the center position is to be determined with reference to the outer circumferential surface of the article, methods such as those shown in FIGS. 4 and 5 are often used. The example shown in FIG. 4 is a well-known method for determining the center position of a cylindrical article 1 using a V block 4.
Even in the measurement method using the block 4, errors in the measurement result of the center position cannot be avoided due to errors in the size and shape of the article. Furthermore, as shown in FIG.
The method of finding the center position by limiting the distance by 3 causes the same inconvenience as in the case of using the inner circumferential surface reference as shown in FIG.

Furthermore, as shown in FIG. 6, the method of abutting one end surface of a square or rectangular object against a block 6 fixed on the upper surface of a surface plate 5 and determining the center position of the object 1 using this end surface as a reference is not possible. , it is necessary to know the dimensions of the article 1 accurately, which not only makes the measurement work troublesome but also makes it difficult to perform precise measurements.

(Object of the Invention) An object of the present invention is to provide a method for positioning an article, which eliminates the above-mentioned inconveniences, allows easy and accurate positioning of an article, and does not damage the article during measurement. It is said that

(Structure of the Invention) The method for positioning an article of the present invention includes uniformly jetting compressed air from a hollow or solid blowing member made of a porous material and whose position is known in advance and which is set on a support plate. A solid or cylindrical object to be positioned is fitted into the current fume member with a small gap in between, and the article is moved by the pressure of the compressed air jetting from the fume member toward the surface of the article. By moving the compressed air a small amount to balance the force of the compressed air pushing the article over the entire circumference of the article, the positional relationship of the article to the blowing member is always constant, and the position of the article is adjusted with respect to the position of the blowing member. This is the way to decide.

(Embodiments of the Invention) Next, the present invention will be explained in more detail with reference to drawings showing embodiments.

FIG. 7 shows an example in which the center position of a cylindrical article is determined by the positioning method of the present invention.
A cylindrical blowhole member 8 made of a porous material obtained by sintering granular metal or the like is planted on the upper surface of the central portion of the support plate 7 . The central axis a of the fumarole member 8 is determined in advance as precisely as possible using an appropriate method, but since the work of determining the central axis a only needs to be performed once, a troublesome method may be used. Considerably accurate measurements can be obtained.

An air reservoir 1 provided inside a support plate 7 rotatably supported by a base plate 10 via a thrust bearing 9
1 is supplied with compressed air through an air passage 12. Furthermore, the compressed air supplied to this air reservoir 11 enters from the bottom surface of the fumarole member 8 exposed to this air reservoir 11 into the fine through holes inside this fume member, and passes through the outer surface of the portion protruding from the support plate 7. It squirts out evenly. The inner diameter of the cylindrical article 1 whose center is to be determined is slightly larger than the outer diameter of the cylindrical blower member 8, and the outer diameter of the blower member 8 is adjusted so that the article 1 can be easily fitted onto the blower member 8. Determine the diameter.

To find the center of the article 1 using the inner circumference as a reference, the article 1 is fitted onto the blowing member 8, and the ventilation passage 12,
The compressed air sent into the fine holes in the fume member 8 through the air reservoir 11 is ejected from the outer circumferential surface of the fume member 8 toward the inner circumferential surface of the article 1. This jetting of compressed air is carried out uniformly over the entire circumference of the fume blown member 8, so when the article 1 is fitted onto the fume blown member 8, there is a gap between the inner circumferential surface of the article 1 and the outer circumferential surface of the fume blown member 8. Even if a deviation occurs between the ends, this deviation is immediately and automatically corrected, the width between the ends becomes the same over the entire circumference, and the center of the article 1 coincides with the center of the blowing member 8. In other words, if there is a deviation between the above distances, the force of the compressed air pushing against the inner peripheral surface of the article 1 will be strong (high pressure) in areas where the gap is narrow, and on the contrary, it will be weak (low pressure) in areas where the gap is wide. Therefore, if there is any deviation, the force of the compressed air will automatically move the article 1 in a direction to equalize the distance, and the center of the article 1 will coincide with the center of the blowing member 8 in a very short time. .

In the illustrated embodiment, since the support plate 7 rotates around the center a of the blowing member 8, the support plate 7 is rotated while keeping the center of the article aligned with the center a by the above-mentioned jet of compressed air. , if the circumferential surface of the article is tracked with the stylus 13 of the comparator, this article 1
It is possible to accurately measure the roundness, etc. of

As mentioned above, the porous material constituting the fumarole member 8 is made by sintering and forming granular metal, and there are countless voids inside it, as shown in FIG. It exists in a maze shape. The surface of the blower member 8, which serves as a positioning reference, has a diameter.
There are countless tiny openings around 10 μm in size. Although the area of each opening is not unified, the amount of compressed air jetted out from the countless openings is uniform on a surface that has a certain extent (area), so the amount of compressed air jetted out is It becomes uniform over the entire surface of the blowing member 8.

Therefore, when compressed air is ejected from the outer circumferential surface of the blower member 8 into the narrow gap between the inner circumferential surface of the article 1 and the outer circumferential surface of the blower member 8, as shown in FIG. The pressure within the above gap becomes uniform over almost the entire gap. As a result, even if the pressure of the compressed air is relatively low, the force supporting the article 1 (in the radial direction) can be sufficiently increased. This is particularly advantageous if the article is easily deformable.

On the other hand, in the case of a structure in which compressed air is ejected from a nozzle hole, as described in JP-A-54-151863, the pressure within the
As shown in Figure 6, it is high near the nozzle hole 19;
As the distance from the nozzle hole 19 increases, the height rapidly decreases. This tendency becomes more pronounced as the width between 〓 becomes smaller. For this reason, if the width between the ends is large, it becomes difficult to support the article with a sufficiently large force. Furthermore, if the width between the edges is made smaller in order to increase the supporting force, the article will be more likely to deform.

Next, FIG. 8 shows a state in which the center position of a cylindrical article is measured by the method of the present invention. The device used for measuring the center position of such an article using the outer circumference as a reference is a device in which a cylindrical holder 14 is fixed to the upper surface of the support plate 7.
A cylindrical blowing member 8 is attached to cover an air reservoir 11 formed all around the inner peripheral surface of the cylinder 4. The center position of this blowing member 8 is also determined in advance as in the case of the first embodiment. The compressed air sent to the outer circumferential side of the blowing member 8 through the ventilation path 12 and the air reservoir 11 is uniformly ejected from the inner circumferential surface of the blowing member 8. Since the inner diameter of the blowing member 8 is formed slightly larger than the outer diameter of the article 1 whose center is to be determined,
When the article 1 is fitted into the fume member 8 and the compressed air supplied through the ventilation path 12 and the air reservoir 11 is blown inside the fume member 8, the inner circumferential surface of the fume member 8 and the outer circumferential surface of the article 1 are The width between the gaps is uniform over the entire circumference, and the center of the article 1 coincides with the center of the blowing member 8. Note that the porosity of the porous material constituting the fumarole member 8 is equivalent to that of the porous material constituting the porous static pressure gas bearing.

In the embodiment described above, the center of the article, which is a rotating body such as a cylindrical or cylindrical column, is made to coincide with the center of the blowing member 8, and the center position of the article 1 is determined. example of a square column), No. 18
Even in the case of the article 1 which is a non-rotating body as shown in the figure (an example of an equilateral triangular prism), the force of compressed air applied to each side is balanced and its center coincides with the center of the fume member 8. Based on the center, the center of the article 1 can be known.

Furthermore, when determining the position of the article by the method of the present invention, the centers of the two do not necessarily have to coincide. For example, as shown in FIG. 19, when an article 1 with a scalene polygonal cross section is fitted into a blower member having an inner hole with a similar cross-sectional shape, there will be a difference in the force pressing the article on each side. , the center positions of both do not necessarily match, but their positional relationship is always constant.
Therefore, even if the centers do not coincide, the article can always be positioned at a fixed location.

(Effects of the Invention) Since the article positioning method of the present invention is configured as described above, it exhibits the following effects.

(1) The position of the article can be determined easily and quickly simply by fitting the article into the blower member.

(2) Due to the averaging effect of the compressed air film, the center position can always be accurately determined with better accuracy than the shape error of the article.

(3) Accuracy is improved compared to conventional methods, achieving an accuracy of 1 μm or less.

(4) Accurate centering work can be performed repeatedly,
Measurements with good reproducibility are possible.

(5) Since uniform force is applied to the object over its entire circumference, the object will not be deformed during measurement.
Items made of flexible materials can also be positioned accurately.

(6) Measurement results are not affected by ambient temperature, etc., and no heat is generated during measurement, so articles, etc. are not deformed by heat.

(7) Since there is no contact with the object during positioning and no strong pressure is applied, the object will not be damaged.

(8) Since the device used for positioning has no moving parts or parts that come into contact with the object, it does not suffer from wear, has a semi-permanent lifespan, and does not deteriorate in accuracy.

(9) Since lubricants such as oil are not used, there is no chance of staining the goods, workers' hands, clothes, etc.

(10) It is possible to find the center position of an article whose cross section is not only circular but also a regular polygon, and it is also possible to determine the position of an article whose cross section is a scalene polygon.

(11) Since the fumarole member is made of porous material, it is possible to strengthen the force that holds the item in place,
This is advantageous when the probe is brought into elastic contact with the outer peripheral surface of the article.

That is, according to the experiment conducted by the present inventor, as shown in FIG.
Nozzle 1 that spouts compressed air upward at m
6, and when trying to support a flat plate 17 with a weight W (Kg) at a distance h above the pedestal 15 using the force of compressed air of 5Kg/cm ² from this nozzle, the weight W and The relationship with distance h is now as shown in FIG. According to this, the smaller the distance h between the top surface of the pedestal and the bottom surface of the flat plate, the more weight can be supported, but when the distance h becomes 10 μm or less, the weight that can be supported does not increase even if the distance becomes smaller. The maximum weight it can support is about 5 kg.

On the other hand, the upper surface of the fumarole plate made of a porous material and having the same shape and size as the upper surface of the pedestal 15 is replaced by a flat plate 1.
7, and apply compressed air of 5Kg/ ^cm2 to the
When the gas was ejected uniformly from the upper surface of the blast plate at a rate of 1/min, the relationship between the distance h between the upper surface of the blast plate and the lower surface of the flat plate and the weight W of the flat plate 17 was as shown in FIG. According to this, the distance h is 10μ
If the weight exceeds m, the weight that can be supported is almost the same as that of the nozzle shown in Fig. 9, but
When h becomes 10 μm or less, the weight that can be supported increases further, reaching a maximum of about 18 kg.

(12) As a result, the pressure of the compressed air used during measurement does not need to be relatively low, so a simple compressed air source is sufficient, and there is no risk of explosion, etc.

(13) Since the fume member 8 made of porous material has countless micropores opening over its entire circumference, the object receives force uniformly over the entire circumference, and the object is not biased and can be heated precisely. Can perform measurements.

(Application example) According to the method of the present invention, the position of the article can be determined easily, quickly and precisely as described above, but it is not only possible to simply determine the position, but also to use the center position determined by positioning as a reference. This method is effective when processing articles as such. In such a case, an external force is applied to the article. If the external force is small, the force of the compressed air ejected from the blowing member 8 can sufficiently support the article, but if a relatively large external force is applied, there is a risk that the center position will shift.

In order to prevent such deviation, the 12th to 13th
As shown in the figure, a recess 18 may be formed on the upper surface of the support plate 7 or holder 14 on which the article 1 is placed, and this recess 18 may be freely connected to a negative pressure source. When processing the object 1 after finding its center, first, the communication between the recess 18 and the negative pressure source is cut off, and then compressed air is jetted out from the blower member 8 to locate the center of the object 1 than the blower member 8. 8, the recess 18 is communicated with a negative pressure source, and the article 1 is attracted to the upper surface of the support plate 7 or the holder 14. As a result, the article 1 whose center position has been determined will not move easily, and the determined center position will not shift even if an external force is applied due to processing or the like.
In each example, a porous material is fitted into the recess 18,
The article 1 may be adsorbed onto the surface of this porous material.

[Brief explanation of drawings]

Figures 1 to 6 show six conventional methods for positioning articles, with Figure 1 being a vertical cross-sectional view of the first example, Figure 2 being a vertical sectional view of the second example, and Figure 3 being a longitudinal sectional view of the third example. Fig. 4 is an end view of the fourth example, Fig. 5 is an end view of the fifth example, and Fig. 6 is an end view of the fifth example.
The figure is a side view of the sixth example, and the following figures are diagrams for explaining the present invention. In figure 7, the center is determined based on the inner periphery of the article, and in the same way, in figure 8, the center is determined based on the outer periphery. Figure 9 is a vertical cross-sectional view of the device used to determine A diagram showing the relationship between the supported weight and the size of the space formed by compressed air. Figure 11 is a similar diagram when using porous material. Figures 12 and 13 are diagrams showing the application of the present invention. FIG. 14 is an enlarged view of part A in FIG. 7, FIG. 15 is a diagram showing the pressure distribution within the gap when the method of the present invention is used, and FIG. 16 is a conventional method. A diagram showing the pressure distribution between 〓 and 〓 in the case of
FIG. 17 is a cross-sectional view showing an example in which a square column is fitted into a similar-shaped hole in a fume member; FIG. 18 is a cross-sectional view showing an example in which an equilateral triangular column is fitted in a similar-shaped hole in a fume member; FIG. 19 is a sectional view showing an example in which a scalene polygonal column is fitted into a similarly shaped hole of a blower member. 1: Article, 2: Pin, 3: Claw, 4: V block, 5: Surface plate, 6: Block, 7: Support plate, 8:
Fumarole member, 9: Thrust bearing, 10: Base plate, 1
1: Air reservoir, 12: Air passage, 13: Stylus, 14:
Holder, 15: pedestal, 16: nozzle, 17: flat plate, 18: recess.

Claims (1)

[Scope of Claims] 1. A method for positioning a hollow cylindrical article, wherein a rod-shaped blowing member made of a porous material and ejecting compressed air uniformly from the outer surface is attached to the article to be positioned on its entire inner surface. A booth is interposed between the product and the product, and the article is moved by the pressure of compressed air that is blown out from the fume member toward the inner surface of the product to maintain a constant positional relationship between the product and the fume member. A method for positioning an article, characterized in that the position of the article is determined based on the position of a blowing member. 2. A method for positioning a solid columnar article, in which a cylindrical blower member made of porous material that uniformly jets compressed air from the inner surface is placed between the article to be positioned and the entire outer surface of the article. A previously known fume member is fitted onto the outside of the article with a A method for positioning an article, the method comprising determining the position of the article based on the position of the article.